Rotary-linear motion converter

ABSTRACT

A rotary-linear motion converter has a rotatable housing and a shaft within the housing offset from the rotary axis thereof and having a number of journal or cam discs eccentrically fixed on the shaft. The journal discs are rotatably positioned within corresponding openings in a corresponding number of slide members which are slidably mounted in the housing for reciprocatory movement so that rotation of the shaft causes the slide members to reciprocate and to rotate the housing.

United States Patent Ryan 1451 Feb. 15, 1972 [54] ROTARY-LINEAR MOTION 2,801,596 8/1957 Sewell ..4l7/273 CONVERTER 2,900,839 8/1959 McKintosh. ..74/57l 2,936,632 5/1960 Palmer ..74/49 Inventor John Ryan, 18 Ellwood Glen Cove, 3,176,667 4/1965 Hammer 123/43 L.l., N.Y. 11542 Primary Examiner-William F, O'Dea [22] Flled 1970 Assistant Examiner-Wesley S. Ratliff, Jr. [21] Appl.No.: 67,944 Att0rneySmythe&Moore [52] US. Cl ..74/49, 91/496, 417/273 [57] ABSTRACT [51 1 Int. Cl ..Fl6h 21/18 A rotary-linear m i n r r h a r t t h ing an a [58] Field 6: Search ..74/49, 571-, 123/43 0, 43 R; shaft within the housing Offset from the rotary axis thereof and 9 49 417 73 having a number of journal or cam discs eccentrically fixed on the shaft. The journal discs are rotatably positioned within [56] References cued corresponding openings in a corresponding number of slide members which are slidably mounted in the housing for UNITED STATES PATENTS reciprocatory movement so that rotation of the shaft causes the slide members to reciprocate and to rotate the housing. 409,563 8/1889 Curtis ..9l/496 733,139 7/1903 Bullock ..74/49 4 Claims, 8 Drawing Figures PATENTEDFEB 15 I972 SHEET 1 OF 3 JOHN J: AY/M/ ATTORNEY) PATENTEBFEBYSBTZ 3,641,828

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SHEET 3 OF 3 Fee.

INVENTOR /o/'//\/ L]. Krmv ATTORNEYS ROTARY-LINEAR MOTION CONVERTER Mechanisms and mechanical movements have been known for converting rotary to linear reciprocating motion and vice versa. Such mechanisms have also been developed where a plurality of axes are involved along each of which there occurs linear movement. Such mechanisms are generally characterized by excessive side or lateral forces which produce an unduly rapid wear of the moving components. The wear is particularly objectionable in those forms of mechanism, such as a pump having a piston and cylinder, which must deliver a precise amount offiuid, or in a fuel pump, which has to deliver precise amounts of liquid fuel to an internal combustion engine. The induced side load on the pistons and any other type of piston mechanism, such as used in pumps, engines, and compressors, tend to produce a wear pattern which is out of round and rapidly reduces the sealing characteristics of the piston within the cylinder. In those mechanisms where the side load can be eliminated, the wear pattern remains round so as to result in a considerably longer piston-cylinder operating life.

A further disadvantage of such prior art mechanisms is that a considerable number of components are required in translating linear motion from a cylindrical to rotary motion of a crankshaft. The use of connecting rods between the pistons and the crankshaft sets up excessive side loads on the sliding member which in the case of engines and pumps is usually a piston within a cylinder. The result is a nonsymmetrical wear between the sliding components which is objectionable in many mechanisms.

It is an object of the present invention to provide an improved mechanism for converting rotary to linear motion and vice versa.

It is another object of the present invention for providing a mechanism for converting rotary to reciprocating motion along a plurality of axes.

It is still another object of the present invention to provide arrangement useable in an internal combustion engine wherein reciprocating motion is converted to rotary motion but which utilizes a considerably fewer number of parts than a conventional engine.

According to one aspect of the present invention, a mechanical movement or mechanism for converting rotary to linear motion may comprise a housing rotatably mounted on a housing shaft and a second shaft within the housing and extending from the housing shaft but offset therefrom. A plurality of cam discs are fixed on the second shaft with their centers offset from the center of the second shaft and equally spaced from each other around the second shaft. Each journal or cam disc is offset a distance equal to the offset distance between the second shaft and the housing shaft. A corresponding plurality of slide members are slidably mounted for reciprocatory movement in the housing, and each slide member has an opening therein for rotatably receiving one of the journal discs. The slide axes of the slide members are equally spaced around the second shaft.

In operation, the housing shaft may be fixed against rotation, and the second shaft may be rotated whereby the second shaft will follow a planetary path around the housing shaft, and the slide members will reciprocate within the housing.

Other objects, advantages and features of the present invention will be apparent from the accompanying description and drawings, which are merely exemplary.

In the drawings:

FIG. 1 is an exploded view showing schematically a mechanism according to the present invention having three reciprocable axes;

FIG. 2 is a vertical sectional view of the mechanism shown in FIG. 1;

FIG. 3A-D schematically illustrate positions of a slide during a cycle of rotation ofa cam disc;

FIG. 4 is a plan view showing schematically an engine utilizing the mechanism in FIG. 1 with portions of the engine being shown in section; and

FIG. 5 is a sectional view taken along the line 5--5 of FIG. 4.

Proceeding next to the drawings wherein like reference symbols indicate the same parts throughout the various views, a specific embodiment of the present invention will be described in detail.

As may be seen in FIG. I, a mechanism according to the present invention is indicated generally at and comprising a housing shaft 11 which is fixed against rotation within a mount 12 by means of a key 13. A cylindrical housing 14 is rotatably mounted on the housing shaft 11.

A second shaft 15, which is in effect a crankshaft. has one end 16 journaled in block 17 which is mounted on the end of the housing shaft 11 by means of a set screw 18. The upper end of the shaft may be rotatably supported in a journal 19. The rotary axis of shaft 15 is parallel to that of shaft 11 but is offset therefrom by a distance A as indicated in FIG. 1.

A plurality of circular journal discs 20, 21 and 22 are fixed eccentrically on the shaft 15 with the centers of these discs being equally spaced from each other around the shaft. Where three cam discs are used, as in the embodiment of FIG. 1, the centers of the discs are spaced 120 apart.

Each of the discs is rotatably received in a correspondingly shaped circular opening formed in blocks 23, 24 and 25 which are slidably positioned by means of rods 26, 27 and 28 in the cylindrical housing 14 for reciprocatory movement therein. A mounting or positioning of the shafts 26, 27 and 28 in the housing 14 may be more clearly seen in FIG. 2. The rods 26 to 28 may be connected to pistons within cylinders, as shown in FIG. 4, or to other suitable devices.

In the operation of the mechanism of FIG. 1, the shaft 11 is fixed against rotation and the housing 14 is rotatable about this shaft. The shaft 15 can be rotated by any suitable mechanism such as through a suitable gearing or drive arrangement indicated generally at 30 in FIG. 2. The axis of rotation of the shaft 15 is now fixed, and the shaft 15 will rotate with the discs 20, 21 and 22 also rotating. As may be seen in FIG. 3, rotation of the disc 20 will cause the slide member shaft 26 to rotate to the positions successively shown in FIGS. 3A-D. Upon a complete revolution of disc 20, the slide shaft 26 will be rotated one-half revolution to the position shown in FIG. 3D. At the same time, the shaft 26 will reciprocate within the housing 14. The housing 14 will thus rotate at one-half the speed of shaft 15.

It is to be noted that the center of disc 20 is offset from the central axis 15 by a distance equal to the offset distance A between shaft 15 and housing shaft 11. The same relationship exists for discs 21 and 22.

While the embodiment of the mechanism, as illustrated in FIG. 1, utilizes three discs, it is pointed out that two equally spaced discs could also be used. Regardless of the number of discs employed, the centers of these discs are spaced equally about the shaft 15.

As an alternative arrangement of the mechanism in FIG. 1, the housing 14 could be fixed against rotation and the housing shaft 11 driven through a suitable source of input power. As a result, the rotation of shaft 11 will rotate the block 17 and, accordingly, the shaft 15 will follow a planetary path while rotating at twice the speed of shaft 11. The rotation and planetary movement of shaft 15 will bring about reciprocatory movement of the several slide member shafts 26, 27 and 28 by the interaction of the respective discs within their-slide blocks 23, 24 and 25, respectively.

Reference to FIGS. 4 and 5, there is shown a modification of the mechanism of FIG. 1 wherein pistons are mounted on the ends of the several slide members. As may be seen in FIG. 4, pistons 31 and 32 are mounted on opposite ends of slide rod 26, pistons 33 and 34 on the opposite ends of slide rod 27 and pistons 35 and 36 on the ends of slide rod 28. Each of these pistons reciprocates within a respective cylinder as shown in FIG. 4 with suitable mechanism being provided for the firing and supplying of fuel to each of the cylinders.

The pistons on opposite ends of a slide rod are rigidly connected so that, in effect, there are three pairs of pistons with each pair of pistons being rigidly connected to each other through a slide rod.

In the operation of the engine of FIGS. 4 and 5, the firing of the cylinders in the appropriate order will cause the reciprocation of the respective slide members 26 to 28. These successive reciprocating movements of the slide rods will cause the shaft to move in a planetary path and, as a result, will rotate the shaft 11 which functions as the output shaft.

It will be understood that various details of construction and arrangement of parts may be made without departing from the spirit of the invention except as defined in the appended claims.

What is claimed is:

1. In a mechanical movement for converting rotary to linear motion, and vice versa, the combination of a housing shaft, a housing rotatably mounted on said housing shaft, a second shaft within said housing and extending from said housing shaft but offset therefrom, a plurality of discs fixed on said second shaft with their centers being offset from the center of the second shaft and equally spaced from each other around said second shaft, each disc being offset equal to the ofiset distance between said second shaft and said housing shaft, a corresponding plurality of slide members slidably mounted in said housing and each having an opening rotatably receiving one of said discs therein, the slide axes of said slide members being equally spaced around said second shaft.

2. In a mechanical movement as claimed in claim I wherein said housing shaft is fixed against rotation and said second shaft is rotated about its axis whereby said housing will be rotated about the housing shaft under the action of the discs rotating within said slide members which slide said housing and rotate about a moving center of rotation.

3. In a mechanical movement as claimed in claim 1 wherein said housing is fixed against rotation and said housing shaft is rotated whereby said second shaft will follow 'a planetary path while rotating at twice the speed of said housing shaft and said slide members will reciprocate within said housing.

4. In a mechanical movement as claimed in claim 3 with there being a piston on each end of a slide member and a cylinder receiving each piston, means operatively associated with each cyiinder and piston for actuating said cylinder and piston in a cycle of an internal combustion engine whereby the reciprocating movement of said slide members rotates said housing shaft. 

2. In a mechanical movement as claimed in claim 1 wherein said housing shaft is fixed against rotation and said second shaft is rotated about its axis whereby said housing will be rotated about the housing shaft under the action of the discs rotating within said slide members which slide said housing and rotate about a moving center of rotation.
 3. In a mechanical movement as claimed in claim 1 wherein said housing is fixed against rotation and said housing shaft is rotated whereby said second shaft will follow a planetary path while rotating at twice the speed of said housing shaft and said slide members will reciprocate within said housing.
 4. In a mechanical movement as claimed in claim 3 with there being a piston on each end of a slide member and a cylinder receiving each piston, means operatively associated with each cylinder and piston for actuating said cylinder and piston in a cycle of an internal combustion engine whereby the reciprocating movement of said slide members rotates said housing shaft. 